Hypoid gears are generally formed with a cutting machine that rotates both a cutter tool and a stock piece of metal while the axis of rotation of the cutter tool and the stock are orientated at an angle. The cutter tool and/or the stock are advanced toward one another, generally along the axis of rotation as the blades of the cutter tool shave material from the stock to form gear teeth on the stock. Some machines will vary the orientation of the cutter tool and/or stock perpendicular to the axis of rotation during cutting to form a desired hypoid tooth shape. Both pinion and ring gears of a hypoid gear set may be cut in this manner.
A gear cutting tool generally includes a plurality of inside cutter blades and a plurality of outside cutter blades extending therefrom to form the teeth of a hypoid gear. Typically, the pinion or ring gear outside cutter blades form the pinion drive side or the ring gear coast side of a hypoid tooth profile and the pinion or ring gear inside cutter blades form the pinion coast side or the ring gear drive side of a hypoid tooth profile. Many cutting tools are dimensioned such that different cutter blades are needed to form the gear teeth of different gear ratios.
A chamfer is commonly applied to the tip of the gear teeth to reduce the acute angular corners that form when the cutter blades remove material from the stock. If not reduced, the corners can be chipped or nicked and cause detrimental noise. Various methods of producing a chamfer exist including, manual filing and the use of gear cutting machines with chamfering attachments. The cutter blades may also be configured with chamfering edges that enable the cutter blades to cut a side of the gear tooth and form a chamfer on the tooth simultaneously. However, this requires a unique top-land radius chamfer tool for each ratio.